Energy assisted magnetic recording (EAMR) or heat assisted magnetic recording (HAMR) technology is intended to be used to increase areal density of information storage devices such as hard disks. In these assisted recording systems, a laser beam is delivered through an optical waveguide and interacts with a near field transducer (NFT) that absorbs part of the optical energy and forms a very strong localized electromagnetic field in the near field region. When the localized electromagnetic field is close enough to the recording medium, the recording medium absorbs part of the localized electromagnetic field energy and is thereby heated up thermally, which helps to realize the magnetic recording process.
The efficiency of the NFT depends on the intensity and polarization direction of electromagnetic field (light) delivered to it through the waveguide(s) in order to induce a desired plasmonic resonance. However, controlling the intensity and polarization direction of electromagnetic field (light) delivered to the NFT includes many challenges.